The Roaring Lion fire capitalized on some exotic wind conditions during its Sunday evening takeoff, and it will have more atypical weather on Tuesday.

“We expect to upgrade to red flag warnings on Tuesday afternoon, when a strong cold front moves in,” National Weather Service meteorologist Genki Kino said Monday. “A cold front this strong for this time of year is unusual.”

The front should bring winds with gusts between 25 and 35 mph through the Bitterroot and Missoula valleys on Tuesday afternoon, with speeds in the mountain ridges topping 50 mph around Tuesday evening. That’s likely to make firefighting on the 3,505-acre Roaring Lion fire 5 miles southwest of Hamilton even more challenging.

About 150 firefighters have been deployed to the blaze, with a Type I incident command team – deployed on the most serious fires – expected to take over operations Tuesday morning. The Roaring Lion fire has triggered evacuations of at least 500 people, with another 1,000 residents on pre-evacuation notice. The fire threatens about 400 primary homes as well as about 100 secondary homes near Hamilton.

Rick Potts has spent the summer at the St. Mary Peak fire lookout, about 23 air miles from Roaring Lion Canyon. Although he served on an initial attack team during the catastrophic Yellowstone National Park fires of 1988, he said he’d never witnessed fire behavior like Sunday’s in the Bitterroots.

“Watching that go from a thin plume of smoke to a roaring inferno within half an hour – I’ve never seen that,” Potts said. “It went from something you might handle with initial attack to something you couldn’t get close to. And the Forest Service and Hamilton Fire (Department) moved on it almost instantly. They had engines and a helicopter up there but by the time they got to it, it exploded up the hill, spotted and started a second fire. It just engulfed the whole mouth of the canyon.”

Many observers noticed the fire and smoke column rotating as it rose on Sunday evening. Kino said that’s because a regular down-canyon evening wind created spinning vortexes as the fire’s uphill heat pushed the opposite direction. The effect is similar to whirlpools that form between the main downstream current of a river and the upstream flow of a streamside eddy. In the Roaring Lion fire, the wind shear also created fire whirls that lifted tornadoes of flame hundreds of feet into the air.

Tuesday’s cold front should pass out of the Bitterroot Mountains area by Wednesday morning. But it will be followed by persistent hot weather leading to a weekend of potential dry thunderstorms. Those storms carry lightning that could trigger more wildfires.

Missoula County fire officials raised the local fire danger status “very high” on Monday.

“All fuels both live and dead have dried to the point that fires will become very active quickly,” said Jordan Koppen, spokesman for the Montana Department of Natural Resources and Conservation. “We can’t afford for anyone to be careless during activities that have the potential to start a fire, so we urge the public to be extremely cautious with fire.”

Koppen added that equipment operators and motorists towing trailers should be especially careful about controlling hot metal and friction sparks while outdoors. More information on fire-safe tactics is available at firesafemt.org.

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On Monday afternoon, the U.S. Department of Homeland Security announced Roaring Lion firefighting efforts were eligible for federal assistance. Federal Emergency Management Agency funds can be used to cover 75 percent of state and local firefighting costs. However, the grants do not provide assistance for individual home or business owners affected by the fire, or other infrastructure damage related to the fire. FEMA spokesman Randy Welch said the money would pay for field camps, equipment use, repairs and replacement, tools materials and supplies.

The increased tempo of fire activity has forced state and federal fire crews to prioritize their resources. Lolo National Forest spokesman Boyd Hartwig said three 20-person Hotshot crews have been released from the 13-acre South Tamarack fire 6 miles north of St. Regis after reaching mop-up status on Monday. A Type-II initial attack crew remains on the scene, where the fire is 20 percent contained.

The Northern Region Geographic Area, which includes Montana, shifted to Preparedness Level 3 on Monday. That reflects the changing tempo of fire starts and need for personnel, equipment and aircraft. The Northern Region remains ranked fourth out of seven geographic areas as fires in Colorado and parts of the Southwest demand higher priority. As dry weather shifts to the Northwest, that priority will shift as well.

Statewide, Montana fire observers reported 15 new fires including two large incidents (Roaring Lion and Copper King). Those come on top of five existing large fires and dozens of smaller blazes.

The Copper King fire 8 miles east of Thompson Falls should move to a Type II incident command management on Tuesday. It has burned about 700 acres. As of Monday, it had a crew of 33 backed up by a helicopter on the line.

While no evacuations have been ordered, residents in the Copper King and Snider communities have been warned to prepare their structures for fire defense.

Several roads along the west side of the Thompson River have been closed for fire safety, as have the Copper King and Clark Memorial campgrounds.

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